Method and system of device identification

ABSTRACT

A medical device susceptible to identification using interference patterns for performing device identification is disclosed. A source signal may be directed from an energy source towards the surface of a device for reflection therefrom. An interference pattern may be detected from the surface of the device, such as by a sensor. A determination as to whether a match exists between the representation of the interference pattern and a stored representation of an interference pattern may be performed. If a match exists, the device may be identified based on the stored representation of the interference pattern. Otherwise, a representation of the interference pattern may be stored and a unique identifier may be assigned to the stored representation of the interference pattern.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of U.S. patent application Ser. No. 11/556,357,filed Nov. 3, 2006, which is incorporated by reference in the entiretyherein.

Not Applicable

BACKGROUND

1. Technical Field

The disclosed embodiments pertain to methods and systems for identifyingdevices. The disclosed embodiments particularly pertain to methods andsystems for identifying devices using speckle patterns.

2. Background

Implantable medical devices can be used to perform a variety offunctions for patients needing medical care. Such devices includerelatively large devices, such as implantable defibrillators, andrelatively small devices, such as bone screws and stents.

In order to provide an appropriate level of patient safety, allimplanted devices, and many non-implanted devices, must be serialized toenable tracking if a part defect, product recall, concerns aboutcounterfeit parts or other reliability issue arises. While a relativelylarge medical device is typically identified by a serial number that iswritten, engraved or otherwise labeled on the device, a smaller deviceis conventionally identified only on its packaging by a serial number ora lot number because such devices are too small to be directly labeledby conventional means. As such, when a small, unlabeled medical deviceis explanted and/or returned to a supplier without its packaging, it canbe impractical or impossible to identify the manufacturing lot fromwhich the device came and/or the serial number assigned to the device.

Adequately identifying small devices can also be problematic in otherfields as well. For example, a small semiconductor device might not besufficiently large to identify the part number, the lot number, themanufacturer and the like.

What is needed is a method and system for uniquely identifying a device,particularly a device that is difficult to directly label with a serialnumber.

A further need exists for a simple and inexpensive process forperforming such identification for medical and non-medical devices.

The present embodiments are directed to solving one or more of theaforementioned problems.

SUMMARY

Before the present methods are described, it is to be understood thatthis invention is not limited to the particular systems, methodologiesor protocols described, as these may vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to limit the scope ofthe present disclosure which will be limited only by the appendedclaims.

It must be noted that as used herein and in the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. Thus, for example, reference to a“device” is a reference to one or more devices, parts and equivalentsthereof known to those skilled in the art, and so forth. Unless definedotherwise, all technical and scientific terms used herein have the samemeanings as commonly understood by one of ordinary skill in the art.Although any methods and materials similar or equivalent to thosedescribed herein can be used in practice or testing of the presentinvention, the preferred methods, devices, and materials are nowdescribed. All publications mentioned herein are incorporated herein byreference. Nothing herein is to be construed as an admission that theinvention is not entitled to antedate such disclosure by virtue of priorinvention.

As a device is manufactured, microscopic and/or other subtle variationsmay occur in the device. Identifying such variations for a particulardevice may enable the variations to be used as an identifying feature.In an embodiment, variations may be introduced in a manufacturingprocess to distinguish devices from each other. Such identification maybe performed with respect to distinguishing a device from other devicesof the same type.

In an embodiment, an energy beam, such as a coherent light source orlaser, may be directed towards a device. The device may cause the energybeam to be scattered resulting in a spatially distributed interferencepattern, also known as a speckle pattern. Microscopic and/or othervariations in material composition of each device may cause thescattering to differ for each device. However, the scattering may bereproducible for a particular device.

Exposing the device to an energy beam may produce a speckle pattern,which may be recorded. In an embodiment, the device may be fully rotatedas part of the speckle pattern recording process. The speckle patternfor a device may be stored and may represent a unique signature oridentifying label for the device.

When a device that has been distributed is returned to a supplier, thedevice may be identified by rescanning the device and comparing theresulting speckle pattern with one or more stored speckle patterns todetermine a match. The speckle patterns may be compared using, forexample, a pattern recognition process, such as a computer automatedpattern recognition process. For example, the speckle pattern for thereturned device may be compared with database entries of specklepatterns produced by all devices that are of the same type as thereturned device. The speckle pattern for the returned device mayalternately be compared with all speckle patterns of all devices sold bythe supplier, produced by a particular manufacturer, or the like.

A pattern recognition process may be used to locate a matching segmentand/or portions of matching segments of the speckle pattern that align.Locating matching segments and/or portions of matching segments may beparticularly useful for identifying damaged and/or worn devices. In anembodiment, a recognition process may detect variations in absoluteintensity of a speckle pattern.

If particular devices are partially or completely composed of a bulkmaterial that is transparent or translucent to the energy beam,particulate matter, such as a metal oxide, may be added to the bulkmaterial to substantially increase the variability of speckle patternsproduced among devices of that type. In an embodiment, the amount ofparticulate matter added to the bulk material may have substantially noeffect on the bulk material's mechanical or chemical properties. If adevice is completely opaque, such as for a device composed of a metal,microscopic differences in surface finish may be introduced by beadblasting and/or other mechanical means if necessary to enhance thespeckle pattern variability.

In an embodiment, a system for performing device identification mayinclude an energy source configured to direct a source signal onto adevice such that the source signal is reflected and/or scattered by thedevice resulting in an interference pattern, a sensor configured tocapture an interference pattern of the reflected signal, and a computingunit configured to store the interference pattern for the device and toassign a unique identifier to the interference pattern for the device.

In an embodiment, a method of performing device identification mayinclude directing a source signal from an energy source towards thesurface of a device for reflection and/or scattering therefrom,detecting an interference pattern from the surfaces of the device, anddetermining whether a match exists between at least a portion of therepresentation of the interference pattern and at least a portion of astored representation of an interference pattern. If a match exists, themethod may further include identifying the device based on the storedrepresentation of the interference pattern. If no match exists, themethod may further include storing a representation of the interferencepattern, and assigning a unique identifier to the representation of theinterference pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects, features, benefits and advantages of the present invention willbe apparent with regard to the following description and accompanyingdrawings, of which:

FIG. 1 depicts an exemplary scanning apparatus for determining a specklepattern according to an embodiment.

FIG. 2 depicts a flow diagram for an exemplary device identificationprocess according to an embodiment.

FIG. 3 is a block diagram of exemplary internal hardware that may beused to contain or implement program instructions according to anembodiment.

DETAILED DESCRIPTION

FIG. 1 depicts an exemplary scanning apparatus for determining a specklepattern according to an embodiment. As shown in FIG. 1, the scanningapparatus may include an energy source 100, one or more sensors 120 anda computing unit 140.

The energy source 100 may comprise a coherent energy source. The mostcommon exemplary coherent energy source may be a coherent light source105, such as a laser. Alternate coherent energy sources 100 may includea sound generator, an ultraviolet or infrared light generator or anyother device capable of generating a coherent wave pattern. In anembodiment, a helium-neon laser having a long coherence length may beused. In an embodiment, a stabilized helium-neon laboratory laser, suchas Melles Griot model 05 STP 901, may be used.

In an embodiment, the energy source 100 may include a coherent lightsource 105 and one or more lenses 110. In an embodiment, the one or morelenses 110 may include a dispersing and collimating lens. The one ormore lenses 110 may be used to disperse and collimate the coherent lightbeam to form a collimated light beam that is wider than the beam emittedfrom the coherent light source 105. In an embodiment, the collimatedlight beam may be wider than a device illuminated by the collimatedlight beam. For example, if the laser has a beam width of 0.5 mm, a beamexpander, such as the Edmund Optics 10× beam expander (model NT55-578),may be used to achieve a 5 mm beam diameter to illuminate the devicebeing scanned.

The device to be interrogated may be mechanically fixtured to achieve arepeatable speckle pattern. In an embodiment, micron or sub-micronrepeatability may be achieved with a mechanical system. For manymaterials, controlling the temperature at which the testing is performedmay be helpful in achieving satisfactory repeatability. Rotating theentire device during the interrogation process may result in partialmatches that may be adequate for uniquely identifying the device.

A sensor 120 may include a photo detector array 125. The photo detectorarray 125 may be a charge coupled device or other suitable imagingdevice. In an embodiment, a filter 130, such as a light filter, may beused to limit the energy reaching the sensor 120 to that produced by theenergy source 100. In an embodiment, each filter 130 may include aninterference filter that produces a narrow pass band to exclude energyhaving a wavelength other than that produced by the energy source 100.For example, a light filter 130 may prevent light not having awavelength substantially similar to a light-emitting energy source 100from passing through the light filter. For example, if a 633 nmhelium-neon laser is used to illuminate the device being scanned, aninterference filter 130, such as the Melles Griot model 03 FIL 218interference filter, may be used to selectively pass only the light fromthe laser. The filter 130 may be placed in close proximity to the photodetector array 125. In an embodiment, a plurality of sensors 120 may beused in which each sensor includes, for example, a photo detector array125 and a light filter 130. Other sensors 120 will be apparent to thoseof ordinary skill in the art based on this disclosure.

The computing unit 140 may be designed to receive data from the sensor120 corresponding to a speckle pattern produced when a device isilluminated by an energy beam from the energy source 100. The computingunit 140 may include, for example and without limitation, a processor145 and a processor-readable storage medium 150. The processor 145 mayinclude a CPU for a computer system, a server or the like. In anembodiment, the processor may be remote from the processor-readablestorage medium. The processor-readable storage medium 150 may include arandom access memory (RAM), a read only memory (ROM), a portable mediumsuch as compact disk, a digital video disk, a USB drive or the like, ahard disk, a remote computing device and/or the like. The computing unit140 may be configured to store speckle patterns received from the sensor120 and assign a unique identifier to the speckle pattern. The uniqueidentifier may be used to identify a device that produced the specklepattern. The computing unit 140 may be further configured to compare areceived speckle pattern for a device with one or more stored specklepatterns to determine whether a match exists and to provide the uniqueidentifier for the matching stored speckle pattern if a match exists.Providing the unique identifier may include, for example, causing theidentifier to be displayed to a user.

FIG. 2 depicts a flow diagram for an exemplary device identificationprocess according to an embodiment. As shown in FIG. 2, the energysource 100 may produce 205 a source signal, such as an energy beam. Thedevice may include, for example and without limitation, a medicaldevice, such as a stent, a pacing lead, a neurological lead, a catheterand the like, a bone screw, a miniplate, a suture sleeve, asemiconductor device or the like. The energy beam may be directedtowards a device that is being identified. In an embodiment, the energybeam may be broader than the device being identified.

The energy beam may impact the surface of the device causing the energybeam to be reflected 210. As the energy beam is reflected and scattered,the interaction of the reflected energy beam may cause constructive anddestructive interference patterns to occur. Such interference patternsmay result in the generation of a speckle pattern.

The sensor 120 may receive 215 reflected energy in the form of a specklepattern. For example, a photo detector array 125 may receive lightenergy that reflects from a device as filtered through a light filter130. The light filter 130 may filter the received light to removesubstantially all ambient light and to only permit the speckle patterncaused by the energy beam to pass. For example, the light filter 130 mayfilter the light of substantially all wavelengths other than a narrowrange corresponding to the wavelength emitted by the energy source.

In an embodiment, the device may be, for example, fully rotated 220(i.e., rotated 360 degrees) when capturing the speckle pattern for thedevice. This may improve the ability to match the speckle pattern fromthe device with a stored speckle pattern if the device is worn or hasbeen damaged. In addition, rotating the device may permit identificationof the device even if the device is partially misaligned. In analternate embodiment, a static speckle pattern may be produced fordevices for which accurate alignment is easily performed, such as byusing a fixture.

Using a plurality of sensors 120 may improve the identification processfor a device. For example, speckle patterns received by each sensor 120may be correlated geometrically to unambiguously identify a device, evenwhen damaged and/or worn.

The speckle pattern information received by a sensor 120 may betransmitted 225 to, for example, a computing unit 140 for postprocessing and storage. In an embodiment, the computing unit 140 maycompare 230 a received speckle pattern for the device with one or morestored speckle patterns to determine whether a match exists. If a matchdoes exist, the computing unit 140 may provide 235 the unique identifierfor the matching stored speckle pattern. Providing 235 the uniqueidentifier may include, for example, causing the identifier to bedisplayed to a user. Acceptable speckle pattern matching algorithms willbe apparent to those of ordinary skill in the art and may be similar toalgorithms used to perform, for example, biometric verification and/orpattern recognition. In an embodiment, a mathematical correlationbetween the speckle pattern for a scanned device and a stored specklepattern may be used. In an embodiment, a match may only exist if adevice has been previously scanned because each device is uniquelyidentified by the speckle pattern which it produces. A device may berescanned, for example, if it had been previously distributed and wasreturned to the supplier due to a defect, a product recall or the like.

If a match does not exist, the computing unit may store 240 the specklepattern or a representation of the speckle pattern and assign 245 aunique identifier to the stored speckle pattern. A representation of thespeckle pattern may correspond to a mathematical computation based onthe information included in the speckle pattern, a value representing afeature of one or more points within a speckle pattern or the like. Theunique identifier may correspond to the stored speckle pattern anduniquely identify the device corresponding to the stored specklepattern.

FIG. 3 is a block diagram of exemplary internal hardware that may beused to contain or implement program instructions according to anembodiment. Referring to FIG. 3, a bus 328 may serve as a maininformation highway interconnecting the other illustrated components ofthe hardware. CPU 302 is the central computing unit of the system,performing calculations and logic operations required to execute aprogram. Read only memory (ROM) 318 and random access memory (RAM) 320constitute exemplary memory devices.

A disk controller 304 interfaces with one or more optional disk drivesto the system bus 328. These disk drives may be, for example, externalor internal CD ROM drives 306, hard drives 308 or DVD drives 310. Asindicated previously, these various disk drives and disk controllers areoptional devices.

Program instructions may be stored in the ROM 318 and/or the RAM 320.Optionally, program instructions may be stored on a computer readablemedium such as a USB key or a digital disk or other recording medium, acommunications signal or a carrier wave.

An optional display interface 322 may permit information from the bus328 to be displayed on the display 324 in audio, graphic or alphanumericformat. Communication with external devices may optionally occur usingvarious communication ports 326. An exemplary communication port 326 maybe attached to a communications network, such as the Internet or anintranet.

In addition to computer-type components and their equivalents, thehardware may also include an interface 312 which allows for receipt ofdata from input devices such as a keyboard 314 or other input device 316such as a remote control, pointer and/or joystick.

A multiprocessor system may optionally be used to perform one, some orall of the operations described herein. Likewise, an embedded system mayoptionally be used to perform one, some or all of the operationsdescribed herein.

It is to be understood that the disclosed embodiments are not limited inapplication to the details of construction and to the arrangements ofthe components or steps set forth in this description or illustrated inthe drawings. The disclosed methods and systems are capable of otherembodiments and of being practiced and carried out in various ways.Hence, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting.

As such, those of ordinary skill in the art will appreciate that theconception upon which this disclosure is based may readily be utilizedas a basis for the designing of other structures, methods and systemsfor carrying out the several purposes of the disclosed embodiments. Itis important, therefore, that the claims be regarded as including suchequivalent constructions insofar as they do not depart from the spiritand scope of the disclosed embodiments.

1. A medical device comprising: at least one surface to whichparticulate matter has been introduced to increase the variability ofspeckle patterns for that device type when the speckle patterns areacquired by reflecting light from a coherent light source off of thedevice and are compared to stored interference patterns to assess theprobability of a match.
 2. A medical device comprising: a body that issubstantially opaque and at least one surface to which microscopicdifferences in a finish of the surface have been introduced bymechanical means to increase the variability of speckle patterns forthat device type when the speckle patterns are acquired by reflectinglight from a coherent light source off of the device and are compared tostored interference pattern to assess the probability of a match.
 3. Themedical device of claim 2 wherein the mechanical means is bead blasting.